Novel photographic products and processes

Abstract

This invention relates to photographic products and processes employing silver halide solvent precursors of the formulae <IMAGE> wherein R1 and R2, the same or different, each are hydrogen, alkyl, phenalkyl, phenyl or phenyl substituted with an electron-donating or electron-withdrawing group; R3 is alkyl, phenalkyl, phenyl or substituted phenyl; Z is -CN or -SO2R4 wherein R4 is branched-chain alkyl, phenalkyl, phenyl or substituted phenyl; and n is an integer 3, 4 or 5.

What is claimed is: 
     
       1. A photographic product which comprises a photosensitive silver halide emulsion layer carried on a support and a silver halide solvent precursor in a layer on the same side of said support as said silver halide emulsion layer, said silver halide solvent precursor being a compound selected from those represented by the formulae ##STR20## wherein R 1  and R 2 , the same or different, each are hydrogen, alkyl, phenalkyl, phenyl, or phenyl substituted with an electron-donating or electron-withdrawing group; R 3  is alkyl, phenalkyl, phenyl, or substituted phenyl; Z is --CN or --SO 2  --R 4  wherein R 4  is branched-chain alkyl, phenalkyl, phenyl, or substituted phenyl and n is an integer 3, 4 or 5. 
     
     
       2. A photographic product as defined in claim 1 which additionally includes a silver halide developing agent in a layer on the same side of said support as said silver halide emulsion layer. 
     
     
       3. A photographic product as defined in claim 1 which additionally includes an additive multicolor screen and a layer comprising silver precipitating nuclei disposed between said support and said silver halide emulsion layer. 
     
     
       4. A photographic product as defined in claim 3 wherein said silver halide solvent precursor is disposed in said silver halide emulsion layer. 
     
     
       5. A photographic product as defined in claim 1 wherein said R 1  and R 2  of formulae I and II are different. 
     
     
       6. A photographic product as defined in claim 5 wherein said silver halide solvent precursor is a compound of formula I. 
     
     
       7. A photographic product as defined in claim 6 wherein said n of formula I is 3. 
     
     
       8. A photographic product which comprises a first sheet-like element comprising a photosensitive silver halide emulsion layer carried on a support, a second sheet-like element adapted to be superposed with said first sheet-like element, means for retaining an aqueous alkaline processing composition for distribution between said first and second sheet-like elements, and a silver halide solvent precursor disposed in one or both of said sheet-like elements, said silver halide solvent precursor being a compound selected from those represented by the formulae ##STR21## wherein R 1  and R 2 , the same or different, each are hydrogen, akyl, phenalkyl, phenyl, or phenyl substituted with an electron-donating or electron-withdrawing group; R 3  is alkyl, phenalkyl, phenyl, or substituted phenyl; Z is --CN or --SO 2  --R 4  wherein R 4  is branched-chain alkyl, phenalkyl, phenyl, or substituted phenyl and n is an integer 3, 4 or 5. 
     
     
       9. A photographic product as defined in claim 8 wherein said silver halide solvent precursor is disposed in said first sheet-like element. 
     
     
       10. A photographic product as defined in claim 8 wherein said R 1  and R 2  of formulae I and II are different. 
     
     
       11. A photographic product as defined in claim 10 wherein said R 1  is hydrogen. 
     
     
       12. A photographic product as defined in claim 11 wherein said silver halide solvent precursor is a compound of formula I. 
     
     
       13. A photographic product as defined in claim 9 wherein one of said first and second sheet-like elements additionally includes an image-receiving layer. 
     
     
       14. A photographic product as defined in claim 13 wherein said image-receiving layer is contained in said second sheet-like element. 
     
     
       15. A photographic product as defined in claim 14 wherein said image-receiving layer is a silver precipitating layer. 
     
     
       16. A photographic product as defined in claim 14 wherein said image-receiving layer is a dye image-receiving layer and said first sheet-like element additionally includes a dye image-forming material associated with said silver halide emulsion layer. 
     
     
       17. A photographic product as defined in claim 16 wherein said dye image-forming material associated with said silver halide emulsion layer is a photographically inert compound capable of undergoing cleavage in the presence of silver ions and/or soluble silver complex to liberate a diffusible dye. 
     
     
       18. A photographic product as defined in claim 17 wherein a silver halide developing agent is disposed in said first sheet-like element. 
     
     
       19. A photographic product as defined in claim 8 wherein said processing composition includes a viscosity-increasing reagent. 
     
     
       20. A photographic process which comprises (a) exposing imagewise a photosensitive element comprising a photosensitive silver halide emulsion layer carried on a support and a silver halide solvent precursor on the same side of said support as said emulsion layer, said silver halide solvent precursor being a compound selected from those represented by the formulae ##STR22##  wherein R 1  and R 2 , the same or different, each are hydrogen, alkyl, phenalkyl, phenyl, or phenyl substituted with an electron-donating or electron-withdrawing group; R 3  is alkyl, phenalkyl, phenyl, or substituted phenyl; Z is --CN or --SO 2  --R 4  wherein R 4  is branched-chain alkyl, phenylalkyl, phenyl, or substituted phenyl and n is an integer 3, 4 or 5 and   (b) applying to said exposed photosensitive element an aqueous alkaline processing composition to effect development of exposed silver halide and to effect release of silver halide solvent from said silver halide solvent precursor, thereby forming an imagewise distribution of silver complex soluble in said aqueous alkaline composition.   
     
     
       21. A photographic process as defined in claim 20 which includes the additional steps of (c) transferring said imagewise distribution of soluble silver complex to a superposed silver-precipitating layer and (d) reducing said transferred silver complex to provide a silver image. 
     
     
       22. A photographic process as defined in claim 20 wherein said photosensitive element includes a dye image-forming material associated with said silver halide emulsion layer and a dye image-receiving layer. 
     
     
       23. A photographic process as defined in claim 22 wherein said dye image-forming material is a photographically inert compound capable of undergoing cleavage in the presence of silver ions and/or soluble silver complex to liberate a diffusible dye and which includes the additional steps of contacting said imagewise distribution of soluble silver complex with said dye image-forming material to form a corresponding imagewise distribution of diffusible dye and transferring said diffusible dye to said dye image-receiving layer to form a dye image thereon.